Lane departure warning (LDW) systems have been developed for vehicles to detect and warn of the vehicle's departure from a lane on a roadway. The LDW system typically employs one or more camera based vision systems mounted to the host vehicle which generate digital images of the roadway and lane markings forward of the vehicle. This may be achieved by monitoring the position of the vehicle relative to the lane boundary markings found on the roadway. A typical roadway may have a lane width of one about hundred forty-six (146) inches, as compared to conventional light duty host vehicle widths which are usually less than eighty (80) inches. The conventional proposed LDW systems typically calculate vehicle lane departure based on the width of the host vehicle. Typically, camera images are processed into scenes by a microprocessor to determine whether the vehicle is expected to be departing from the lane of the roadway based on processed image algorithms and a threshold width value, which typically is based on the width of the host vehicle.
While the currently proposed lane departure warning system may serve adequately well to determine departure of a vehicle from the roadway, limitations or drawbacks exist when the vehicle is towing a trailer, particularly, a trailer having a width wider than the host driving vehicle. For example, a trailer may have a width of one hundred two (102) inches, which is substantially greater than the width of the host vehicle. The conventional proposed LDW system operates based on the width of the host vehicle and may not adequately detect when the trailer first departs from the lane due to its extended width. The large discrepancy between the host vehicle width and the trailer width allows the trailer to depart from the lane before the conventional proposed LDW system may alert the driver of such an event.
Accordingly, it is therefore desirable to provide for an enhanced lane departure warning system that effectively detects the departure of the vehicle and its towed trailer from a lane on a roadway and does not suffer from the drawbacks or limitations of the conventional proposed LDW systems.